Process of producing cyanine dyestuffs



United States Patent PROCESS or PRODUCING CYANINE DYESTUFFS John David Kendall, Harold Gordon Suggate, and John Henry Mayo, llford, England, assignors to llford Limited, Ilford, England, a British company No Drawing. Application November 26, 1951, Serial No. 258,304

Claims priority, application Great Britain December 5, 1950 3 Claims. (Cl. 260-240) This invention relates to the production of dyestuffs which have utility as optical sensitisers for photographic emulslons.

According to the present invention dyestuifs having utility as optical sensitisers for photographic emulsions have the general Formula I:

where D1 is the residue of a S-membered or 6-membered heterocyclic nitrogen nucleus, R1 is an alkyl or aralkyl group, Y is an alkyl, aralkyl, aryl or heterocyclic group, X is a nitrile group, Z is a nitrile group or an esterified carboxylic acid group, and n and m are the same or different and are each nought or 1.

According further to the present invention the said dyestuffs are produced by condensing an intermediate of general Formula II:

Rzci \Z II where R2 is a hydrogen or hydrocarbon group (preferably lower alkyl), or where R2CH2 and Y together form an isocyclic ring, e. g. cyclohexanone or cyclopentanone, and otherwise Y, X and Z have the meanings assigned to them above, with a compound of general formula:

where Q is an alkyl thioether group or an NHR4 group where R4 is aryl or acylaryl residue, R3 is an alkyl or aralkyl group, X is an acid residue, D2 is the residue of a S-membered or 6-membered heterocyclic nitrogen ring, and n and m are the same or different and each is nought or 1. The CH2 group of the RzCHz grouping is reactive and one of its hydrogen atoms splits out with the radicle Q to yield a dyestuif of the general Formula I.

The intermediate of general Formula II may be made by the method of Widequist, Acta Chem. Scand., 3, 303/304, 1949; Chem. Abs., 43, 7901b, 1949.

In carrying out the reaction the preferred procedure is to dissolve equimolecular quantities of the intermediates in alcohol, add one molecular equivalent of an acid binding agent, e. g. triethylamine, and gently reflux the mixture for about half an hour. On cooling the mixture and diluting with water the required dyestuff usually separates. Instead of triethylamine there may be employed: sodium acetate, potassium carbonate, sodium chloride, pyridine or caustic soda.

It might reasonably have been expected that when Y is a methyl or other lower alkyl group it might also be reactive so that reaction would occur both on the Y group and the RzCHz group, but in fact no clear evidence of such a reaction has been found.

Where any of the symbols in the formulae given above may represent alkyl groups these may be methyl, ethyl, propyl, butyl or higher alkyl. Where any of them represent aralkyl groups these may be, for example, benzyl 2,697,707 Patented Dec. 21, 1954 groups, and where any of them represent aryl groups these may be, for example, phenyl or naphthyl groups. The residues D1 and D2 may be the residues of any S-membered or 6-membered heterocyclic nitrogen nucleus commonly employed in cyanine dyes, e. g. thiazoles, oxazoles, selenazoles and their polycyclic homologues, such as those of the benzene, naphthalene, acenaphthene and anthracene series, pyridine and its polycyclic homologues such as quinoline and a and 8 naphthoquinolines, lepidines, indolenines, diazines such as pyrimidines and quinazolines, diazoles such as thio-flfi diazole, oxazolines, thiazolines and selenazolines. The polycyclic compounds of these series may be substituted in the carbocyclic rings by one or more groups such as alkyl, aryl, amino, hydroxy, alkoxy and methylene-dioxy groups or by halogen atoms. The following examples will serve to illustrate the 1nvent1on:

EXAMPLE 1 Preparation of methylisopropylidene cyanoacetate Methyl cyanoacetate (37.25 gms.) was added to chloroform (37.5 cc.), acetone (28 gms.), ammonium acetate (3 gms.) and acetic acid (4.5 cc.) and the mixture boiled gently under reflux for 2 hours, using an extractor from which the water split out in the reaction was removed manually at intervals of about 15 minutes. The mixture was cooled, washed with water and the chloroform solution dried over sodium sulphate. The chloroform was distilled off and the residual oil distilled in vacuo. The product, obtained as a colourless oil, had B. P. 9697 C. at 3 mm. pressure.

EXAMPLE 2 Preparation of 2-cyan0-3-ethyl-2-pentenonitrile Malononitrile (20 gms.) was added to diethyl ketone (30 gms.), chloroform (40 cc.), ammonium acetate (2.5 gms.) and glacial acetic acid (4 cc.) and the mixture boiled gently under reflux for 2 hours using an extractor from which the water split out during the reaction was removed manually at intervals of about 15 minutes. The mixture was cooled and the chloroform solution washed with water and dried over sodium sulphate. The chloroform was distilled off and the residual oil distilled in vacuo. The product, obtained as a pale yellow oil, had B. P. C. at 8 mm. pressure.

EXAMPLE 3 Ethyl-6-(-3-ethyl-2:3-dihydr0benzthiazolylidene-Z-) -3- methyl-Z-cyano-Z:4-hexadienoate 2-w-acetanilidovinylbenzthiazole ethiodide (2.245 gms.; .005 mol.) was boiled gently under reflux in ethyl alcohol (20 cc.) with ethyl isopropylidenecyanoacetate (.765 gms.; .005 mol.) and triethylamine (.75 cc.; .005 mol.) for 20 minutes giving a deep red/mauve solution. On cooling and dilution dark mauve crystals separated. M. Pt. 193 C.

The crystals were extracted with benzene in a Soxhlett extractor and the benzene solution concentrated under reduced pressure to about 15 ccs. Dilution with light petroleum ether gave crystals, M. Pt. 198 C.

crystallisation from ethyl alcohol gave dark blue crystals, M. Pt. 199 C.

This dyestufi, when incorporated in a silver iodobromide emulsion, extended the sensitivity to about 6400 A. with indeterminate maxima at 5400 A. and 5900 A.

EXAMPLE 4 Ethyl-4-(3-methyl-2:3-dihydr0benzthiaZolylidene-ZJ 3-methyl-2-cyan0-2-buten0ate Z-methylthiobenzthiazole (.905 gms.; .005 mol.) was fused with methyl toluene-p-sulphonate (.93 gms.; .005 mol.) for 4 hours at C. Ethyl alcohol (20 cc.), ethyl isopropylidenecyanoacetate (.765 gms.; .005 mol.) and triethylamine (.75 cc.; .005 mol.) were added and the mixture boiled gently under reflux for 20 minutes 3 giving a yellow solution. On cooling and dilution yellow crystals separated. M. Pt. 200 C. nec'rystanisatieu from ethyl alcohol gave yellow crystals, M. Pt. 204 C.

This dyestufi, when incorporated in a silver chloride emulsion, extended the 'sensitivitytoabout 4950 A. with maximum at about 4400 A. and 4650 A.

EXAMPLE Ethyl--(-3-ethyl 2:3 dihydrobenzthiazolylidene-Z-) -3- m'ethyl-2-cyan0-2 '14 6 8-decatetraenoate Dilution with light This dyestufi, when incorporated in a silver iodobromide emulsion, extended the sensitivity from 5900 A. to about 7300 A. with maximum at about 6800 )1.

EXAMPLE 6 4-(3-methyl-2:3-dihydrabenzthiaz0lylidene-2-) -3 methyl- 10 2-cyano-2-butenonitrile 2-methylthiobenzthiazole (.905 gm; .005 mol.) was fused with methyl toluene-p-sulphonate (.93 gm.; .005 mol.) for 4 hours at 120 C. Ethyl alcohol cc.), isopropylidenemalononitrile (.53 gm.; .005 mol.) and triethylamine (.75 cc.; .005 mol.) were added and the mixture boiled gently under reflux for 20 minutes giving a yellow solution. On cooling and dilution orange crystals separated, M. Pt. 284 'C. Recrystallisation from ethyl alcohol gave orange crystals, M. Pt. 288 C.

This dyestufi, when incorporated in a silver chloride emulsion, extended the sensitivity from 4200 A. to 5000 A.

with maximum at about 4900 A.

The following are further examples of intermediates prepared by processes strictly analogous to those set forth in Examples 1 and 2.

FROM ETHYL OYANOACETATE Example No. Ketone used R2 Y X Z M. P. or B. P. 0.

tone H OH; ON COOC4H5 B. P. 989 C. atl mm. Methyl Ethyl CH3 CH4 ON 000mm B.'P.112 0. at 3 mm. tllyl CH: C2H5 CN COOCH5 B. P. 114 Cyat 6 mm. Aeetophenone H 0115 ON COOG2H5 B. P. 178-9" 0. at 8 mm. Propiophenone CH C H ON COOC2H5 B. P. 164-1? 0. at 6 mm.

Cyclopentanone -(CH0)4 ON COOO2H5 M. 1. 58 C. Cyclohexanone (CH2)5 ON COOCzHs B. P. 148-9 C. at 8 mm.

MesitylOxlde H CH CN COOCzHs B. P. 138140 C. at 10 mm.

FROM METHYL CYANOAOETATE 15 .Z-Aeetyl Thiophene--. H U ON COOCH; M. P. C.

FROM MALONONITRILE 10 H CH; ON ON B. P. 01 C. at 3.5mm. 17 Ethyl methyl CH3 CH; CN CN B. P. 102 C. at 8 mm. 18 Benzyl methyl CsHs CH; ON ON B. P. 1745 C. at 10 mm.

, The following are fu'rther examples of dyestuffs prepared by processes strictlyanalo'gous to those set forth in the foregoing'Examples 3 to '6 inclusive.

In the final column of these tables the symbol C1 or IBrdenotes whetherthe test was-made in silver chloride 65 or silver iodobromide emulsion, the symbol E denotes the limit of sensitivity imparted by the dye, and the symbol M denotes the region of maximum sensitivity imparted by the dye.

FROM METHYL ISOPROPYLIDENE OYANAOETATE (B. P. 004 0. AT 3 MM.)

Example No. gg gg D1 is R1 '0 m X Y Z Sensitisiug-Data c1. 10 Benzthiazolm. 0H: 0 0 ON CH: 000cm 224 E. 4,950 .1.

M. 4.300 .1. and 4,055 .4.

20 .do mm 0 0 ON cm 00003. 210 E..5,100 A.

M. 4,300 l. and 4,700 l.

21 Quinoline CH4 0 0 ON on: 0000114 1015.000 g.

13 4,050 .4. and- 5,400 K. 22 fi Nephthathiazole CH4 0 0 ON 0H4 0000114 23a E.'5,000 A. M. 4,800 l.

FROM ETHYL ISOPROPYLIDENE OYANAOETATE (B. P. 98-99" 0. AT 1 MM.)

Example No. igg gf g Dlis R; m x Y z 4,6 Sensitising Data.

. 01. 2s 10511501155015 05m- ON on. 00005115 104 10. 4,0501.

1. 24 05111011115 0m 0 GM 0315 0000111, 127 12.5,9001. I 1 1 5,500 A. 25 fl-Napthathiazole 0115 0 ON CH; 00005115 215 11.5.1001.

M. 4,000 A. and 4,0001. E 5501. Benzoxa 1 OH 1 ON on OOOOH 154 1 m 15.4.1100 1.15001. and

5,400 l. 27 Omnnlina OH; 1 CN CH5 COOORHI 187 l. M. 8.0001. 2s 3:3-Dim0thyl 1110515111110 CH: 1 ON 011, 0000511, 208 gr A. 20 5.6-Dimethoxybenzthiazo1e... cm 0 ON 0H5 00005115 230 $3 1 51.140010110430011. 30,... fi-Methyl benzoxazole CH5 0 ON CH0 COOCzH5 181 E] '4,550 j M. 4,350 A. 31 fl-Naphthathiazole cm 1 ON om 00005115 254 {521 L 15.455011.

FROM ETHYL 2-BUTYLIDENE OYANOAOETATE (B. P. 112 0. AT 8 MM.)

1 01. 32 35115511155515 cm 0 ON 01m 00005115 155 11.4,050 A. 0 1 4,7001. 53 05 05B. 0 ON 01115 00005111 121 05,0001.

1 1 4.40011. 1111017501. 04 1201110151515 cm 0 ON 0121, 00001111 121 05.05031.

1g 4,400A. 111104.700 Z1. 35 B-Naphthathiazole on. 0 on 011:, 00001115 202 1115.050 1.

M. 4,500 A. and 4,000 1.

FROM ETHYL 2-QYANO-3:5-DIMETHYL-2:4-HEXADIENOATE (B. P. 1ss-140 0. 1'1 10 MM.)

011 C1 35 B-Naphthathiazole 0m 0 ON CH5 00005115 213 E. 5,100 A. M. 4,3501.

FROM ETHYL-2-OYANO-BFPHENYL-Z-BUTENOATE (B. P. 170-170 0. AT 5 MM.

01. 37 Benzthia OH; 0 ON O5H5 OOOC1H5 177 E. 4,950 A. 1 1 1 1700 3.

r. a as Quinoline OH: 0 ON C0H5 000011515 108 E. 5,0501. 11/1 1,030 A.

1. a9 Benzoxamln OH: 1 CN C0H5 00005115 243 E.6,150 1g.

' M. 4,800 A. and 5,800 A.

40 p-Naphthathiazole on. 0 ON 00H; 00005115 238 4:-

FROM ETHYL-zoYANo-s-BENzYL-mUTENONITRILE (B. P. 111-5 0. AT 10 MM.)

5 IBr. 41 Benzthiamln OH: 0 ON H: ON 217 E. 5,300 A. H5 M. 4.000 A.

M. P. Example N0. gg gg R1 n W Y Z a Q Sensltlsing Data 01. 42 fl-N p on, .0 ON 000011. 240 5,550 A. a M. 5,1003.

1B1. 43 Benzthlazole on. 0 1 CN 000011, 191 1}. M. 0,150 A.

IBr. 44 mm. m1 on, 0 1 ON 0000113 203 E. 0,7501. M. 5,100.1. s

FROM ISOPROPYLIDENE MALONONIIRILE (B. P. 91 0. at as MM.)

, o1. 45 Rnnvfhimnln OQHE 0 0 CN 0H3 ON 215 E.5,000A 161].4,850A 40 fl-Naphthathlazole on; 0 0 ON on; ON 300 10.405015. 1g 4,80011 47 mmmm on: 0 0 ON om ON 250 EJ533003 IBr. 40..---. 130mm n1 01H. 0 0 ON on. ON 200 10.4 001 FROM 2-OYANO-3-E'1HYL-2-BUTENONITRILE (B. P 102 O AT 8 MM.)

01. 49 Benzthiazole on; 0 0 ON 02H; ON 227 4,700 A.

I. 50-.-. mmflim on. 0 0 ON 02H. ON 133 5,8001}. 0

pg teso 11.01111 5,050. 1.

1. a 51 Benzthiazole can 0 0 ON 0.13. ON 108 E. 4,000 A. M. 4,700 3..

EXAMPLE 52 rings, with a compound of the formula:

Ethyl-4-(-3-methyl-4:S-benz 2:3 dihydrobenzthiazolylidene-2-) -2-cyano-3 :4-trimethylene-Z-butenoate Z-methylthio 3-naphthathiazole (1.15 gms.; .005 mol.)

was fused with methyl p-toluene sulphonate (.93 gm.; .005 mol.) for 4 hours at 130 C. Ethyl alcohol (25 cc.), ethyl cyclopentylidene cyanoacetate (.895 gm.; .005 mol.) and triethylamine (.75 cc.; .005 mol.) were added and the mixture boiled gently under reflux for z 20 minutes, giving a yellow solution. On cooling and dilution orange crystals separated, M. Pt. 243 C. Crystallisation from ethyl alcohol gave M. Pt. 246 C. Recrystallisation from ethyl alcohol gave orange crystals, M. Pt. 247 C.

This dyestulf, when incorporated in a silver chloride emulsion, extended the sensitivity to 5300 A. with maximum at 5000 A.

It is to be understood that this invention includes the new dyestufis per se, their processes of production hereinbefore described, and photographic silver halide emulsions containing them.

What we claim is:

Process for the production of dyestulfs which comprises condensing a compound of the formula:

where Q is selected from the class consisting of alkyl thioether and acetanilido groups, R3 is selected from the class consisting of alkyl and benzyl groups, X is an acid residue, D2 is the radicle of a nucleus selected from the class consisting of S-membered and 6-membered heterocyclic nuclei, n is selected from nought and 1 and m is selected from nought and 1.

2. Process according to claim 1 wherein the reaction is carried out in the presence of an acid binding agent.

3. Process according to claim 1 wherein the reaction is carried out by refluxing the reagents in alcoholic solution in the presence of triethylamine.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Chem. Abstracts 16:3101 (Abstract of Brit. Med. Jour., 1922, I, 514-515).

Chem. Abstracts 19:530 (Abstracts of Proc. Roy. Soc., London, 968, 317-333, 1924). 

